The present invention relates to a removable magnetic recording/reproducing device capable of loading and unloading a magnetic recording disk, such as a flexible disk drive carrying out data recording and reproducing relative to a flexible disk and, in particular, to a data protective structure which is effective when an eject button is pushed during data writing relative to a magnetic recording medium of a magnetic recording disk.
The following explanation deals with a flexible disk drive as a removable magnetic recording/reproducing device, but is also applicable to other removable magnetic recording/reproducing devices.
As is well known in the art, a flexible disk drive is a device for performing data recording and reproducing relative to a flexible disk inserted therein. In recent years, the flexible disk has been improved to have a greater capacity. For example, a large-capacity flexible disk having a storage capacity of 128 Mbytes has been developed while a normal-capacity flexible disk has a storage capacity of 1 Mbyte to 2 Mbytes. Following this, a flexible disk drive has also been developed which is capable of data recording and reproducing relative to such a large-capacity flexible disk.
Hereinafter, a flexible disk drive capable of data recording and reproducing relative to a magnetic disk medium (magnetic recording medium) of only the large-capacity flexible disk will be referred to as a high-density dedicated flexible disk drive, while a flexible disk drive capable of data recording and reproducing relative to a magnetic disk medium of only the normal-capacity flexible disk will be referred to as a normal-density dedicated flexible disk drive. On the other hand, a flexible disk drive capable of data recording and reproducing relative to magnetic disk mediums of both the large-capacity and normal-capacity flexible disks will be referred to as a high-density/normal-density flexible disk drive. Further, the high-density dedicated flexible disk drive and the high-density/normal-density flexible disk drive will be collectively referred to as a high-density flexible disk drive.
One of differences in mechanism between the normal-density dedicated flexible disk drive and the high-density flexible disk drive resides in structure of drive units each for moving a carriage holding a magnetic head in a predetermined radial direction with respect to the magnetic disk medium of the flexible disk loaded in the disk drive. Specifically, the normal-density dedicated flexible disk drive employs a stepping motor as the drive unit, while the high-density flexible disk drive employs a linear motor, such as a voice coil motor (VCM), as the drive unit.
Hereinbelow, the voice coil motor employed in the high-density flexible disk drive as the drive unit will be briefly explained. The voice coil motor includes a voice coil disposed rearward of the carriage and wound around a drive shaft extending in parallel to the foregoing predetermined radial direction, and a magnetic circuit for producing a magnetic field intersecting the electric current flowing through the voice coil. With this arrangement, when the electric current is caused to flow through the voice coil in a direction intersecting the magnetic field produced by the magnetic circuit, a drive force is generated in an extending direction of the drive shaft based on interaction between the electric current and the magnetic field. This drive force causes the carriage to move in the foregoing predetermined radial direction.
There is no substantial difference in appearance between the large-capacity flexible disk and the normal-capacity flexible disk. However, since a track width (track pitch) of the large-capacity flexible disk is narrower than that of the normal-capacity flexible disk, servo signals for positional detection are written on the magnetic disk medium of the large-capacity flexible disk.
It is assumed that an eject button is pushed during data writing relative to a magnetic disk medium of a flexible disk in either of the normal-density dedicated flexible disk drive and the high-density flexible disk drive. In this case, not only the data writing is disabled, but also data written on the magnetic disk medium is destroyed. Particularly, since, as described above, the servo signals are written on the magnetic disk medium of the large-capacity flexible disk, those servo signals are also destroyed so that a position control of a magnetic head is made impossible.
Under the circumstances, such a data protective structure has been demanded, wherein, even if the eject button is depressed in error during data writing relative to the magnetic disk medium, data written on the magnetic disk medium is protected. Further, in addition to the protection of data written on the magnetic disk medium, it has been also demanded that the magnetic disk medium is prevented from a substantial damage upon ejection of the flexible disk from the disk drive caused by such erroneous depression of the eject button.